Cold hydrogen

A gas-liquid-particle process termed cold hydrogenation has been developed for this purpose. The hydrogenation is carried out in fixed-bed operation, the liquefied hydrocarbon feed trickling downwards in a hydrogen atmosphere over the solid catalyst, which may be a noble metal catalyst on an inert carrier. Typical process conditions are a temperature of 10°-20°C and a pressure of 2.5-7 atm gauge. The hourly throughput is as high as 20-kg hydrocarbon feed per liter of catalyst volume. 

Cold hydrogenation may also be used for the selective hydrogenation of butadiene and for the selective hydrogenation of methyl acetylene and pro-padiene in propylene feedstocks (K22). 

The combination of CO shift with membrane separation of H2 and in situ C02 capture is mentioned as an advanced process to optimize the hydrogen yield LHV-based cold hydrogen efficiencies of 72% are reported in such configurations.93... 

Cold Hydrogenation A process for selectively hydrogenating petroleum fractions made by steam-reforming, in order to produce gasoline. Developed by Bayer and now in use in 70 refineries and chemical complexes worldwide. 

Ralthydrierung [German, meaning cold hydrogenation] A process for selectively hydrogenating pyrolysis gasoline, a petroleum refining byproduct, at temperatures below 100°C. A palladium catalyst is used. 

Characteristics of the coals are summarised in Table I. The reactors were of the tubing bomb type and the initial (cold) hydrogen pressure was 7 MPa. A sulphided Mo catalyst was introduced to the coal by impregnation from an aqueous solution of ammonium tetrathiomolybdate. 

The coal-oil-catalyst paste and an excess of hydrogen (300 to 500 cubic meters per ton of brown coal paste, 500 to 1000 cubic meters per ton of bituminous coal paste) are pumped at 250 to 300 atmospheres pressure through a heat exchanger and a gas-fired preheater into the reactors. The reactants enter the first of three or four converters at about 430° C. (806° F.) and are rapidly heated to 470° to 490° C. (878° to 915° F.) by the exothermic heat of the hydrogenation reaction. The temperature in the reactors is kept in the range 470° to 490° C. (878° to 915° F.) by injection of about 1000 cubic meters of cold hydrogen per ton of coal paste. 

C3 Hydrorefining. The aim of C3 hydrorefining is to hydrogenate methylacetylene and propadiene present in the cut. Efficient liquid-phase processes were developed by Bayer314-316 (cold hydrogenation process carried out at 10-20°C) and IFP,317 but hydrogenation in the gas phase is also practiced. 

The work would not have been done without the help of the members of the ultra cold hydrogen group at MIT, namely T.J. Greytak, D. Landhuis, S.C. Moss, L. Matos, J. Steinberger and K.M. Vant. The work is supported by the National Science Foundation and the U.S. Office of Naval Research. 

Lastest report on the Munich cold hydrogen beam experiment see M. Nier-ing, R. Holzwarth, J. Reichert, P. Pokasov, Th. Udem, M. Weitz, T.W. Hansch, P. Lemonde, G. Santarelli, M. Abgrall, P. Laurent, C. Salomon, A. Clairon Phys. Rev. Lett. 84, 5496 (2000)... 

A severe hydrotreating plant will have a flow scheme similar to the hydrofinishing unit shown in Fig. 1.11. Hydrocracking is a highly exothermic reaction, so cold hydrogen must be injected at several points in the catalyst bed to moderate the temperature rise. Operating conditions are severe, with pressures of 100-180 bar and reaction temperatures of 350 20°C. 

This is the well-known Horsehead nebula in the constellation Orion. It is made mostly of dust, plus some cold hydrogen gas, and it stands out in silhouette against a more distant mass of hot, luminous hydrogen. It is similar to the great black rift and the indistinct dark clouds which obscure great sections of the veil of stars in the Milky Way. 

Plastic hydrogenation has recently been used for the conversion of various polymers PE, PP, PS, PET and mixtures. The reactions are usually conducted in autoclaves at temperatures around 400 °C, under pressures of cold hydrogen up to 150 atm, and in some cases in the presence of solvents. Enhanced activities are obtained by means of a variety of catalysts. 

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